Compensating wheeled structure



Oct. 18, 1938. f W. F. HEROLD RC- 20,884

COMPENSATING vWHEELED STRUCTURE Original Filed June 5, 1955 Fly.

I za f4 /9 INVENTOR WALTER FTF-1551x113- ATTORNEY Reissued Oct. 18, 1938 UNITED STATES PATENT OFFICE COMPENSATING WHEELED` STRUCTURE Walter F. Herold, Bridgeport, Conn., assignor to The Bassick Company, Bridgeport, Conn., a corporation of Connecticut 2 Claims.

The present invention relates to a compensating wheeled structure and has application in any type of wheeled structure Where a compensating action is desired. While the invention may be incorporated in casters or other wheeled structures of any suitable type it is particularly adapted for heavy duty as for instance casters as employed on trucks. An object of the invention is to provide a compensating wheeled structure in which the compensating action takes place in a rubber tension element. Another object is to provide a compensating wheeled structure in which the compensating means is arranged withr in the wheel and which may be incorporated in the wheeled structure Without materially changing its normal construction or design. Another object is to provide a compensating wheeled structure in which the compensating means is adapto ed to build up pressure as the load is increased, and also to gradually reduce the extent of the compensating movement as the load is increased.

It is particularly proposed to provide compensating means in the form of a torsional joint of rubber or other suitable resilient material interposed between the wheel supporting or supported structure and the wheel bearing, the wheel bearing being eccentric to the torsional joint. The rubber is preferably in the form of a cylinder disposed under permanent stress and tension between two coaxial members disposed one within the other and to each of Which the rubber member is in effect bonded, the relative movement between these coaxial members being resiliently supported by the tension produced by torsional strain in the compressed rubber.

Another object is to provide compensating means which will be noiseless in operation, will not deteriorate to any appreciable extent even after long and excessive use, and will require no lubrication.

With the above and other objects in view, an embodiment of the invention is shown in the accompanying drawing, and this embodiment will be hereinafter more fully described with reference thereto, and the invention will be finally pointed out in the drawing.

In the drawing:

Fig. 1 is a side elevation of a compensating caster, embodying the present invention, the dotand-dash lines representing the full deflected position of the caster wheel.

Fig. 2 is a horizontal sectional View taken along the line 2-2 of Fig. 1.

Fig. 3 is a perspective view of the torsion element employed.

Similar reference characters indicate correspending parts throughout the several figures of the drawing.

Referring to the drawing the compensating caster according to the exemplary illustrated embodiment of the invention, comprises a caster horn of conventional type having .a top portion Ill and side legs II-I I, the top portion I being swivelly connected in the usual manner to a top plate I2. The caster horn is provided in each of the side leg portions I I with a bolt receiving aperture I3 and with inwardly embossed vertically extending ribs I4-I4 extending above and below the respective apertures, for the purpose of rig- 1 idly locking the spindle to the horn as will presently more fully appear.

The torsion element comprises an outer member I5 constituting the wheel bearing and provided with an eccentrically disposed passage I6 20 therethrough, an inner tubular member I1, and a cylindrical body of rubber I8 between them, this rubber body being highly stressed and confined between the members I5 and I1 and being in effect bonded to their surfaces, so that upon' relative rotary movement between the members I5 and IT the rubber body is put under torsional strain. In practice the rubber body is bonded to the inner member I1, as by vulcanization and is then forced into the passage I6 of the outer member I5 under great pressure, its diameter prior to insertion in the member I5 being considerably greater than the diameter of the passage IB, so that the rubber is thus highly stressed and is in effect bonded to the surface of the passage IB by the great surface friction set up between them under stress.

The ends of the rubber project beyond the ends of the member I5, and the ends of the inner member I1 project beyond the rubber member and are provided with grooves I9 which are 40 adapted to be interlockingly engaged with the ribs I4 of the side legs II of the horn, a tie-bolt having a head at one end being engaged through the bore of the member I1 and through the apertures |3-I3 and having a nut 2| screwed upon its threaded end, this asse-mbly rigidly connecting the member Il to the ho-rn and providing a. supporting spacer or strut between the side legs of the horn.

The member I5 which constitutes a bearing 50 for the wheel is provided at one end with an outwardly extending annular flange 22 and at its other end with screw threads 23. Roller bearings 24 supported in a suitable cage 25 are engaged about the member I5, and the wheel 26 55 having a, bearing bushing 21 inserted and secured therein is engaged with the roller bearings, a retaining ring 2B being screwed upon the screwthreaded end 23 of the member I5 to retain the roller bearings and the wheel against lateral displacement. The diameter of the iiange 22 and the ring 28 being greater than the internal diameter of the bushing 21 the ends of the bushing are thus retained against lateral displacement by abutment with the flange 22 and ring 28.

In the normal position of the wheel the member I is disposed with its widest radial dimension extending from the axis of the member I1 in a horizontal piane and projecting forwardly with respect to the caster horn. As load is imposed upon the caster or when the same strikes an obstruction the member I5 will swing upwardly in counter-clockwise direction about the member I1 causing the rubber member to become tensioned through the torsional strain set up therein, the tension gradually building up as the upward swing of the wheel member I5 increases, so that as there is an increased load upon the wheel there is increased tension in the rubber element to compensate for and support it. As the member I5 reaches a position where its wide radius with respect to the axis of the member I1 is in a vertical plane no further movement in counter-clockwise direction takes'place, and in this position the load is solidly supported, as the rubber is under such high stress that it will support the member I'I against radial displacement with respect to the member I5 under any of the usual loads that may be supported upon the caster. As the wheel swings upwardly the amount of vertical movement for a given angular movement gradually decreases, at the same time decreasing the amount of offset of the wheel axis from the swiveling axis, so that as the load gets heavier torsional strains set up in the horn due to oiset are decreased, and the caster or other wheeled structure is therefore capable of efiiciently carrying the heavier loads. With this invention the offset may be substantially greater than in usual caster designs, so that upon reaching the maximum load position, indicated by the ydot-and-dash lines in Fig. l, the oiset will be substantially the same as that obtaining in said usual caster designs. At the same time the greater offset under light loads results in increased mechanical advantage in swivelling and also in the compensating and cushioning action of the caster. The casters are self-leveling when used on trucks, so that they all remain in contact with the ioor at all times, and the cushioning action is such that even with hard treads upon the wheels the casters will be as easy-riding and noiseless as pneumatic tired wheels.

I have illustrated and described a preferred and satisfactory embodiment of my invention, but it will be obvious that changes may be made therein, within the spirit and scope thereof as defined in the appended claims.

Having thus described my invention what I claim and desire to secure by Letters Patent is:-

1. In a compensating wheeled structure, a wheel carrying member including a spindle, an eccentric bearing member disposed about said spindle in spaced relation, a wheel mounted upon said eccentric member, and a body of rubber disposed in highly stressed and conned relation between said spindle and said bearing member constituting both a torsion element and a load support between said spindle and said bearing member, the stress of said body of rubber being such as to prevent relative radial displacement between said spindle and said bearing member,

said bearing member adapted to rotate about said spindle as load is imposed upon the wheel structure to tension said rubber body through torsional strain set up therein.

2. In a compensating wheeled structure, a wheel carrying member comprising a pair of spaced side arms, a spindle rigidly secured to and extending between said side arms, an eccentric bearing member having a bore axially engaged by said spindle in concentrically spaced relation and a cylindrical periphery eccentric to said bore and spindle, a wheel mounted upon said eccentric bearing member in concentric surrounding relationto said outer cylindrical surface and having rotary bearing thereon, and a body of rubber disposed in confined relation in the bore of said bearing member between said spindle and said bore constituting both a torsion element and a load support between said spindle and said bearing member, said bearing member adapted to rotate about said spindle as load is imposed upon the wheel structure to tension said rubber body through torsional strain set up therein.

WALTER F. HEROLD. 

